//	---------------------------------------------------------------------------
//
//	@file		TwOpenGL.cpp
//	@author		Philippe Decaudin
//	@license	This file is part of the AntTweakBar library.
//				For conditions of distribution and use, see License.txt
//
//	---------------------------------------------------------------------------

#if !defined ANT_TW_NO_LEGACY_GL

#include "TwPrecomp.h"
#include "LoadOGL.h"
#include "TwOpenGL.h"

namespace AntTweakBar {

using namespace std;

static const char *g_ErrCantLoadOGL    = "Cannot load OpenGL library dynamically";
static const char *g_ErrCantUnloadOGL  = "Cannot unload OpenGL library";

GLuint g_SmallFontTexID = 0;
GLuint g_NormalFontTexID = 0;
GLuint g_LargeFontTexID = 0;

//	---------------------------------------------------------------------------
//	Extensions

typedef void (APIENTRY * PFNGLBindBufferARB)(GLenum target, GLuint buffer);
typedef void (APIENTRY * PFNGLBindProgramARB)(GLenum target, GLuint program);
typedef GLuint (APIENTRY * PFNGLGetHandleARB)(GLenum pname);
typedef void (APIENTRY * PFNGLUseProgramObjectARB)(GLuint programObj);
typedef void (APIENTRY * PFNGLTexImage3D)(GLenum target, GLint level, GLint internalformat, GLsizei width, GLsizei height, GLsizei depth, GLint border, GLenum format, GLenum type, const GLvoid *pixels);
typedef void (APIENTRY * PFNGLActiveTextureARB)(GLenum texture);
typedef void (APIENTRY * PFNGLClientActiveTextureARB)(GLenum texture);
typedef void (APIENTRY * PFNGLBlendEquation)(GLenum mode);
typedef void (APIENTRY * PFNGLBlendEquationSeparate)(GLenum srcMode, GLenum dstMode);
typedef void (APIENTRY * PFNGLBlendFuncSeparate)(GLenum srcRGB, GLenum dstRGB, GLenum srcAlpha, GLenum dstAlpha);
typedef void (APIENTRY * PFNGLBindVertexArray)(GLuint array);
typedef void (APIENTRY * PFNGLEnableVertexAttribArray) (GLuint index);
typedef void (APIENTRY * PFNGLDisableVertexAttribArray) (GLuint index);
typedef void (APIENTRY * PFNGLGetVertexAttribiv) (GLuint, GLenum, GLint*);
PFNGLBindBufferARB _glBindBufferARB = NULL;
PFNGLBindProgramARB _glBindProgramARB = NULL;
PFNGLGetHandleARB _glGetHandleARB = NULL;
PFNGLUseProgramObjectARB _glUseProgramObjectARB = NULL;
PFNGLTexImage3D _glTexImage3D = NULL;
PFNGLActiveTextureARB _glActiveTextureARB = NULL;
PFNGLClientActiveTextureARB _glClientActiveTextureARB = NULL;
PFNGLBlendEquation _glBlendEquation = NULL;
PFNGLBlendEquationSeparate _glBlendEquationSeparate = NULL;
PFNGLBlendFuncSeparate _glBlendFuncSeparate = NULL;
PFNGLBindVertexArray _glBindVertexArray = NULL;
PFNGLEnableVertexAttribArray _glEnableVertexAttribArray = NULL;
PFNGLDisableVertexAttribArray _glDisableVertexAttribArray = NULL;
PFNGLGetVertexAttribiv _glGetVertexAttribiv = NULL;
#ifndef GL_ARRAY_BUFFER_ARB
#	define GL_ARRAY_BUFFER_ARB 0x8892
#endif
#ifndef GL_ELEMENT_ARRAY_BUFFER_ARB
#	define GL_ELEMENT_ARRAY_BUFFER_ARB 0x8893
#endif
#ifndef GL_ARRAY_BUFFER_BINDING_ARB
#	define GL_ARRAY_BUFFER_BINDING_ARB 0x8894
#endif
#ifndef GL_ELEMENT_ARRAY_BUFFER_BINDING_ARB
#	define GL_ELEMENT_ARRAY_BUFFER_BINDING_ARB 0x8895
#endif
#ifndef GL_VERTEX_PROGRAM_ARB
#	define GL_VERTEX_PROGRAM_ARB 0x8620
#endif
#ifndef GL_FRAGMENT_PROGRAM_ARB
#	define GL_FRAGMENT_PROGRAM_ARB 0x8804
#endif
#ifndef GL_PROGRAM_OBJECT_ARB
#	define GL_PROGRAM_OBJECT_ARB 0x8B40
#endif
#ifndef GL_TEXTURE_3D
#	define GL_TEXTURE_3D 0x806F
#endif
#ifndef GL_TEXTURE0_ARB
#	define GL_TEXTURE0_ARB 0x84C0
#endif
#ifndef GL_ACTIVE_TEXTURE_ARB
#	define GL_ACTIVE_TEXTURE_ARB 0x84E0
#endif
#ifndef GL_CLIENT_ACTIVE_TEXTURE_ARB
#	define GL_CLIENT_ACTIVE_TEXTURE_ARB 0x84E1
#endif
#ifndef GL_MAX_TEXTURE_UNITS_ARB
#	define GL_MAX_TEXTURE_UNITS_ARB 0x84E2
#endif
#ifndef GL_MAX_TEXTURE_COORDS
#	define GL_MAX_TEXTURE_COORDS 0x8871
#endif
#ifndef GL_TEXTURE_RECTANGLE_ARB
#	define GL_TEXTURE_RECTANGLE_ARB 0x84F5
#endif
#ifndef GL_FUNC_ADD
#	define GL_FUNC_ADD 0x8006
#endif
#ifndef GL_BLEND_EQUATION
#	define GL_BLEND_EQUATION 0x8009
#endif
#ifndef GL_BLEND_EQUATION_RGB
#	define GL_BLEND_EQUATION_RGB GL_BLEND_EQUATION
#endif
#ifndef GL_BLEND_EQUATION_ALPHA
#	define GL_BLEND_EQUATION_ALPHA 0x883D
#endif
#ifndef GL_BLEND_SRC_RGB
#	define GL_BLEND_SRC_RGB 0x80C9
#endif
#ifndef GL_BLEND_DST_RGB
#	define GL_BLEND_DST_RGB 0x80C8
#endif
#ifndef GL_BLEND_SRC_ALPHA
#	define GL_BLEND_SRC_ALPHA 0x80CB
#endif
#ifndef GL_BLEND_DST_ALPHA
#	define GL_BLEND_DST_ALPHA 0x80CA
#endif
#ifndef GL_VERTEX_ARRAY_BINDING
#	define GL_VERTEX_ARRAY_BINDING 0x85B5
#endif
#ifndef GL_MAX_VERTEX_ATTRIBS
#	 define GL_MAX_VERTEX_ATTRIBS 0x8869
#endif
#ifndef GL_VERTEX_ATTRIB_ARRAY_ENABLED
#	 define GL_VERTEX_ATTRIB_ARRAY_ENABLED 0x8622
#endif

//	---------------------------------------------------------------------------

#ifdef _DEBUG
	static void CheckGLError(const char *file, int line, const char *func)
	{
		int err=0;
		char msg[256];
		while( (err=_glGetError())!=0 )
		{
			sprintf(msg, "%s(%d) : [%s] GL_ERROR=0x%x\n", file, line, func, err);
			#ifdef ANT_WINDOWS
				OutputDebugString(msg);
			#endif
			fprintf(stderr, msg);
		}
	}
#	ifdef __FUNCTION__
#		define CHECK_GL_ERROR CheckGLError(__FILE__, __LINE__, __FUNCTION__)
#	else
#		define CHECK_GL_ERROR CheckGLError(__FILE__, __LINE__, "")
#	endif
#else
#	define CHECK_GL_ERROR ((void)(0))
#endif

//	---------------------------------------------------------------------------

static GLuint BindFont(const CTexFont *_Font)
{
	GLuint TexID = 0;
	_glGenTextures(1, &TexID);
	_glBindTexture(GL_TEXTURE_2D, TexID);
	_glPixelStorei(GL_UNPACK_SWAP_BYTES, GL_FALSE);
	_glPixelStorei(GL_UNPACK_LSB_FIRST, GL_FALSE);
	_glPixelStorei(GL_UNPACK_ROW_LENGTH, 0);
	_glPixelStorei(GL_UNPACK_SKIP_ROWS, 0);
	_glPixelStorei(GL_UNPACK_SKIP_PIXELS, 0);
	_glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
	_glPixelTransferf(GL_ALPHA_SCALE, 1);
	_glPixelTransferf(GL_ALPHA_BIAS, 0);
	_glPixelTransferf(GL_RED_BIAS, 1);
	_glPixelTransferf(GL_GREEN_BIAS, 1);
	_glPixelTransferf(GL_BLUE_BIAS, 1);
	_glTexImage2D(GL_TEXTURE_2D, 0, 4, _Font->m_TexWidth, _Font->m_TexHeight, 0, GL_ALPHA, GL_UNSIGNED_BYTE, _Font->m_TexBytes);
	_glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
	_glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
	_glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_NEAREST);
	_glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_NEAREST);
	_glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
	_glBindTexture(GL_TEXTURE_2D, 0);
	_glPixelTransferf(GL_ALPHA_BIAS, 0);
	_glPixelTransferf(GL_RED_BIAS, 0);
	_glPixelTransferf(GL_GREEN_BIAS, 0);
	_glPixelTransferf(GL_BLUE_BIAS, 0);

	return TexID;
}

static void UnbindFont(GLuint _FontTexID)
{
	if( _FontTexID>0 )
		_glDeleteTextures(1, &_FontTexID);
}

//	---------------------------------------------------------------------------

int CTwGraphOpenGL::Init()
{
	m_Drawing = false;
	m_FontTexID = 0;
	m_FontTex = NULL;
	m_MaxClipPlanes = -1;

	if( LoadOpenGL()==0 )
	{
		g_ErrorState = g_ErrCantLoadOGL;
		return 0;
	}

	// Get extensions
	_glBindBufferARB = reinterpret_cast<PFNGLBindBufferARB>(_glGetProcAddress("glBindBufferARB"));
	_glBindProgramARB = reinterpret_cast<PFNGLBindProgramARB>(_glGetProcAddress("glBindProgramARB"));
	_glGetHandleARB = reinterpret_cast<PFNGLGetHandleARB>(_glGetProcAddress("glGetHandleARB"));
	_glUseProgramObjectARB = reinterpret_cast<PFNGLUseProgramObjectARB>(_glGetProcAddress("glUseProgramObjectARB"));
	_glTexImage3D = reinterpret_cast<PFNGLTexImage3D>(_glGetProcAddress("glTexImage3D"));
	_glActiveTextureARB = reinterpret_cast<PFNGLActiveTextureARB>(_glGetProcAddress("glActiveTextureARB"));
	_glClientActiveTextureARB = reinterpret_cast<PFNGLClientActiveTextureARB>(_glGetProcAddress("glClientActiveTextureARB"));
	_glBlendEquation = reinterpret_cast<PFNGLBlendEquation>(_glGetProcAddress("glBlendEquation"));
	_glBlendEquationSeparate = reinterpret_cast<PFNGLBlendEquationSeparate>(_glGetProcAddress("glBlendEquationSeparate"));
	_glBlendFuncSeparate = reinterpret_cast<PFNGLBlendFuncSeparate>(_glGetProcAddress("glBlendFuncSeparate"));
	_glBindVertexArray = reinterpret_cast<PFNGLBindVertexArray>(_glGetProcAddress("glBindVertexArray"));
	_glEnableVertexAttribArray = reinterpret_cast<PFNGLEnableVertexAttribArray>(_glGetProcAddress("glEnableVertexAttribArray"));
	_glDisableVertexAttribArray = reinterpret_cast<PFNGLDisableVertexAttribArray>(_glGetProcAddress("glDisableVertexAttribArray"));
	_glGetVertexAttribiv = reinterpret_cast<PFNGLGetVertexAttribiv>(_glGetProcAddress("glGetVertexAttribiv"));

	m_SupportTexRect = false; // updated in BeginDraw

	return 1;
}

//	---------------------------------------------------------------------------

int CTwGraphOpenGL::Shut()
{
	assert(m_Drawing==false);

	UnbindFont(m_FontTexID);

	int Res = 1;
	if( UnloadOpenGL()==0 )
	{
		g_ErrorState = g_ErrCantUnloadOGL;
		Res = 0;
	}

	return Res;
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::BeginDraw(int _WndWidth, int _WndHeight)
{
	assert(m_Drawing==false && _WndWidth>0 && _WndHeight>0);
	m_Drawing = true;
	m_WndWidth = _WndWidth;
	m_WndHeight = _WndHeight;

	CHECK_GL_ERROR;

//#if !defined(ANT_OSX)
	static bool s_SupportTexRectChecked = false;
	if (!s_SupportTexRectChecked)
	{
		const char *ext = (const char *)_glGetString(GL_EXTENSIONS);
		if( ext!=0 && strlen(ext)>0 )
			m_SupportTexRect = (strstr(ext, "GL_ARB_texture_rectangle")!=NULL);
		s_SupportTexRectChecked = true;
	}
//#endif

	_glPushAttrib(GL_ALL_ATTRIB_BITS);
	_glPushClientAttrib(GL_CLIENT_ALL_ATTRIB_BITS);

	if( _glActiveTextureARB )
	{
		_glGetIntegerv(GL_ACTIVE_TEXTURE_ARB, &m_PrevActiveTextureARB);
		_glGetIntegerv(GL_CLIENT_ACTIVE_TEXTURE_ARB, &m_PrevClientActiveTextureARB);
		GLint maxTexUnits = 1;
		_glGetIntegerv(GL_MAX_TEXTURE_COORDS, &maxTexUnits); // was GL_MAX_TEXTURE_UNITS_ARB
		if( maxTexUnits<1 )
			maxTexUnits = 1;
		else if( maxTexUnits > MAX_TEXTURES )
			maxTexUnits = MAX_TEXTURES;
		GLint i;
		for( i=0; i<maxTexUnits; ++i )
		{
			_glActiveTextureARB(GL_TEXTURE0_ARB+i);
			m_PrevActiveTexture1D[i] = _glIsEnabled(GL_TEXTURE_1D);
			m_PrevActiveTexture2D[i] = _glIsEnabled(GL_TEXTURE_2D);
			m_PrevActiveTexture3D[i] = _glIsEnabled(GL_TEXTURE_3D);
			_glDisable(GL_TEXTURE_1D);
			_glDisable(GL_TEXTURE_2D);
			_glDisable(GL_TEXTURE_3D);
		}
		_glActiveTextureARB(GL_TEXTURE0_ARB);

		for( i=0; i<maxTexUnits; i++ )
		{
			_glClientActiveTextureARB(GL_TEXTURE0_ARB+i);
			m_PrevClientTexCoordArray[i] = _glIsEnabled(GL_TEXTURE_COORD_ARRAY);
			_glDisableClientState(GL_TEXTURE_COORD_ARRAY);
		}
		_glClientActiveTextureARB(GL_TEXTURE0_ARB);
	}

	_glMatrixMode(GL_TEXTURE);
	_glPushMatrix();
	_glLoadIdentity();
	_glMatrixMode(GL_MODELVIEW);
	_glPushMatrix();
	_glLoadIdentity();
	_glMatrixMode(GL_PROJECTION);
	_glPushMatrix();
	GLint Vp[4];
	_glGetIntegerv(GL_VIEWPORT, Vp);
	/*
	if( _WndWidth>0 && _WndHeight>0 )
	{
		Vp[0] = 0;
		Vp[1] = 0;
		Vp[2] = _WndWidth;
		Vp[3] = _WndHeight;
		_glViewport(Vp[0], Vp[1], Vp[2], Vp[3]);
	}
	_glLoadIdentity();
	//_glOrtho(Vp[0], Vp[0]+Vp[2]-1, Vp[1]+Vp[3]-1, Vp[1], -1, 1); // Doesn't work
	_glOrtho(Vp[0], Vp[0]+Vp[2], Vp[1]+Vp[3], Vp[1], -1, 1);
	*/
	if( _WndWidth>0 && _WndHeight>0 )
	{
		Vp[0] = 0;
		Vp[1] = 0;
		Vp[2] = _WndWidth-1;
		Vp[3] = _WndHeight-1;
		_glViewport(Vp[0], Vp[1], Vp[2], Vp[3]);
	}
	_glLoadIdentity();
	_glOrtho(Vp[0], Vp[0]+Vp[2], Vp[1]+Vp[3], Vp[1], -1, 1);
	_glGetIntegerv(GL_VIEWPORT, m_ViewportInit);
	_glGetFloatv(GL_PROJECTION_MATRIX, m_ProjMatrixInit);

	_glGetFloatv(GL_LINE_WIDTH, &m_PrevLineWidth);
	_glDisable(GL_POLYGON_STIPPLE);
	_glLineWidth(1);
	_glDisable(GL_LINE_SMOOTH);
	_glDisable(GL_LINE_STIPPLE);
	_glDisable(GL_CULL_FACE);
	_glDisable(GL_DEPTH_TEST);
	_glDisable(GL_LIGHTING);
	_glEnable(GL_BLEND);
	_glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	_glGetTexEnviv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, &m_PrevTexEnv);
	_glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
	_glGetIntegerv(GL_POLYGON_MODE, m_PrevPolygonMode);
	_glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
	_glDisable(GL_ALPHA_TEST);
	//_glEnable(GL_ALPHA_TEST);
	//_glAlphaFunc(GL_GREATER, 0);
	_glDisable(GL_FOG);
	_glDisable(GL_LOGIC_OP);
	_glDisable(GL_SCISSOR_TEST);
	if( m_MaxClipPlanes<0 )
	{
		_glGetIntegerv(GL_MAX_CLIP_PLANES, &m_MaxClipPlanes);
		if( m_MaxClipPlanes<0 || m_MaxClipPlanes>255 )
			m_MaxClipPlanes = 6;
	}
	for( GLint i=0; i<m_MaxClipPlanes; ++i )
		_glDisable(GL_CLIP_PLANE0+i);
	m_PrevTexture = 0;
	_glGetIntegerv(GL_TEXTURE_BINDING_2D, &m_PrevTexture);

	_glDisableClientState(GL_VERTEX_ARRAY);
	_glDisableClientState(GL_NORMAL_ARRAY);
	_glDisableClientState(GL_TEXTURE_COORD_ARRAY);
	_glDisableClientState(GL_INDEX_ARRAY);
	_glDisableClientState(GL_COLOR_ARRAY);
	_glDisableClientState(GL_EDGE_FLAG_ARRAY);

	if( _glBindVertexArray!=NULL )
	{
		m_PrevVertexArray = 0;
		_glGetIntegerv(GL_VERTEX_ARRAY_BINDING, (GLint*)&m_PrevVertexArray);
		_glBindVertexArray(0);
	}
	if( _glBindBufferARB!=NULL )
	{
		m_PrevArrayBufferARB = m_PrevElementArrayBufferARB = 0;
		_glGetIntegerv(GL_ARRAY_BUFFER_BINDING_ARB, &m_PrevArrayBufferARB);
		_glGetIntegerv(GL_ELEMENT_ARRAY_BUFFER_BINDING_ARB, &m_PrevElementArrayBufferARB);
		_glBindBufferARB(GL_ARRAY_BUFFER_ARB, 0);
		_glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, 0);
	}
	if( _glBindProgramARB!=NULL )
	{
		m_PrevVertexProgramARB = _glIsEnabled(GL_VERTEX_PROGRAM_ARB);
		m_PrevFragmentProgramARB = _glIsEnabled(GL_FRAGMENT_PROGRAM_ARB);
		_glDisable(GL_VERTEX_PROGRAM_ARB);
		_glDisable(GL_FRAGMENT_PROGRAM_ARB);
	}
	if( _glGetHandleARB!=NULL && _glUseProgramObjectARB!=NULL )
	{
		m_PrevProgramObjectARB = _glGetHandleARB(GL_PROGRAM_OBJECT_ARB);
		_glUseProgramObjectARB(0);
	}
	_glDisable(GL_TEXTURE_1D);
	_glDisable(GL_TEXTURE_2D);
	if( _glTexImage3D!=NULL )
	{
		m_PrevTexture3D = _glIsEnabled(GL_TEXTURE_3D);
		_glDisable(GL_TEXTURE_3D);
	}

	if( m_SupportTexRect )
	{
		m_PrevTexRectARB = _glIsEnabled(GL_TEXTURE_RECTANGLE_ARB);
		_glDisable(GL_TEXTURE_RECTANGLE_ARB);
	}
	if( _glBlendEquationSeparate!=NULL )
	{
		_glGetIntegerv(GL_BLEND_EQUATION_RGB, &m_PrevBlendEquationRGB);
		_glGetIntegerv(GL_BLEND_EQUATION_ALPHA, &m_PrevBlendEquationAlpha);
		_glBlendEquationSeparate(GL_FUNC_ADD, GL_FUNC_ADD);
	}
	if( _glBlendFuncSeparate!=NULL )
	{
		_glGetIntegerv(GL_BLEND_SRC_RGB, &m_PrevBlendSrcRGB);
		_glGetIntegerv(GL_BLEND_DST_RGB, &m_PrevBlendDstRGB);
		_glGetIntegerv(GL_BLEND_SRC_ALPHA, &m_PrevBlendSrcAlpha);
		_glGetIntegerv(GL_BLEND_DST_ALPHA, &m_PrevBlendDstAlpha);
		_glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	}
	if( _glBlendEquation!=NULL )
	{
		_glGetIntegerv(GL_BLEND_EQUATION, &m_PrevBlendEquation);
		_glBlendEquation(GL_FUNC_ADD);
	}
	if( _glDisableVertexAttribArray!=NULL )
	{
		GLint maxVertexAttribs;
		_glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &maxVertexAttribs);
		if(maxVertexAttribs>MAX_VERTEX_ATTRIBS)
			maxVertexAttribs=MAX_VERTEX_ATTRIBS;

		for(int i=0; i<maxVertexAttribs; i++)
		{
			_glGetVertexAttribiv(i, GL_VERTEX_ATTRIB_ARRAY_ENABLED, &m_PrevEnabledVertexAttrib[i]);
			_glDisableVertexAttribArray(i);
		}
	}

	CHECK_GL_ERROR;
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::EndDraw()
{
	assert(m_Drawing==true);
	m_Drawing = false;

	_glBindTexture(GL_TEXTURE_2D, m_PrevTexture);
	if( _glBindVertexArray!=NULL )
		_glBindVertexArray(m_PrevVertexArray);
	if( _glBindBufferARB!=NULL )
	{
		_glBindBufferARB(GL_ARRAY_BUFFER_ARB, m_PrevArrayBufferARB);
		_glBindBufferARB(GL_ELEMENT_ARRAY_BUFFER_ARB, m_PrevElementArrayBufferARB);
	}
	if( _glBindProgramARB!=NULL )
	{
		if( m_PrevVertexProgramARB )
			_glEnable(GL_VERTEX_PROGRAM_ARB);
		if( m_PrevFragmentProgramARB )
			_glEnable(GL_FRAGMENT_PROGRAM_ARB);
	}
	if( _glGetHandleARB!=NULL && _glUseProgramObjectARB!=NULL )
		_glUseProgramObjectARB(m_PrevProgramObjectARB);
	if( _glTexImage3D!=NULL && m_PrevTexture3D )
		_glEnable(GL_TEXTURE_3D);
	if( m_SupportTexRect && m_PrevTexRectARB )
		_glEnable(GL_TEXTURE_RECTANGLE_ARB);
	if( _glBlendEquation!=NULL )
		_glBlendEquation(m_PrevBlendEquation);
	if( _glBlendEquationSeparate!=NULL )
		_glBlendEquationSeparate(m_PrevBlendEquationRGB, m_PrevBlendEquationAlpha);
	if( _glBlendFuncSeparate!=NULL )
		_glBlendFuncSeparate(m_PrevBlendSrcRGB, m_PrevBlendDstRGB, m_PrevBlendSrcAlpha, m_PrevBlendDstAlpha);

	_glPolygonMode(GL_FRONT, m_PrevPolygonMode[0]);
	_glPolygonMode(GL_BACK, m_PrevPolygonMode[1]);
	_glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, m_PrevTexEnv);
	_glLineWidth(m_PrevLineWidth);
	_glMatrixMode(GL_PROJECTION);
	_glPopMatrix();
	_glMatrixMode(GL_MODELVIEW);
	_glPopMatrix();
	_glMatrixMode(GL_TEXTURE);
	_glPopMatrix();
	_glPopClientAttrib();
	_glPopAttrib();

	if( _glActiveTextureARB )
	{
		GLint maxTexUnits = 1;
		_glGetIntegerv(GL_MAX_TEXTURE_COORDS, &maxTexUnits); // was GL_MAX_TEXTURE_UNITS_ARB
		if( maxTexUnits<1 )
			maxTexUnits = 1;
		else if( maxTexUnits > MAX_TEXTURES )
			maxTexUnits = MAX_TEXTURES;
		GLint i;
		for( i=0; i<maxTexUnits; ++i )
		{
			_glActiveTextureARB(GL_TEXTURE0_ARB+i);
			if( m_PrevActiveTexture1D[i] )
				_glEnable(GL_TEXTURE_1D);
			if( m_PrevActiveTexture2D[i] )
				_glEnable(GL_TEXTURE_2D);
			if( m_PrevActiveTexture3D[i] )
				_glEnable(GL_TEXTURE_3D);
		}
		_glActiveTextureARB(m_PrevActiveTextureARB);

		for( i=0; i<maxTexUnits; ++i )
		{
			_glClientActiveTextureARB(GL_TEXTURE0_ARB+i);
			if( m_PrevClientTexCoordArray[i] )
				_glEnableClientState(GL_TEXTURE_COORD_ARRAY);
		}
		_glClientActiveTextureARB(m_PrevClientActiveTextureARB);
	}
	if(_glEnableVertexAttribArray)
	{
		GLint maxVertexAttribs;
		_glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &maxVertexAttribs);
		if(maxVertexAttribs>MAX_VERTEX_ATTRIBS)
			maxVertexAttribs=MAX_VERTEX_ATTRIBS;

		for(int i=0; i<maxVertexAttribs; i++)
		{
			if(m_PrevEnabledVertexAttrib[i]!=0)
				_glEnableVertexAttribArray(i);
		}
	}

	CHECK_GL_ERROR;
}

//	---------------------------------------------------------------------------

bool CTwGraphOpenGL::IsDrawing()
{
	return m_Drawing;
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::Restore()
{
	UnbindFont(m_FontTexID);
	m_FontTexID = 0;
	m_FontTex = NULL;
}


//	---------------------------------------------------------------------------

void CTwGraphOpenGL::DrawLine(int _X0, int _Y0, int _X1, int _Y1, color32 _Color0, color32 _Color1, bool _AntiAliased)
{
	assert(m_Drawing==true);
	/*
	// border adjustment NO!!
	if(_X0<_X1)
		++_X1;
	else if(_X0>_X1)
		++_X0;
	if(_Y0<_Y1)
		++_Y1;
	else if(_Y0>_Y1)
		++_Y0;
	*/
	//const GLfloat dx = +0.0f;
	const GLfloat dx = +0.5f;
	//GLfloat dy = -0.2f;
	const GLfloat dy = -0.5f;
	if( _AntiAliased )
		_glEnable(GL_LINE_SMOOTH);
	else
		_glDisable(GL_LINE_SMOOTH);
	_glDisable(GL_TEXTURE_2D);
	_glMatrixMode(GL_MODELVIEW);
	_glLoadIdentity();
	_glBegin(GL_LINES);
		_glColor4ub(GLubyte(_Color0>>16), GLubyte(_Color0>>8), GLubyte(_Color0), GLubyte(_Color0>>24));
		_glVertex2f((GLfloat)_X0+dx, (GLfloat)_Y0+dy);
		_glColor4ub(GLubyte(_Color1>>16), GLubyte(_Color1>>8), GLubyte(_Color1), GLubyte(_Color1>>24));
		_glVertex2f((GLfloat)_X1+dx, (GLfloat)_Y1+dy);
		//_glVertex2i(_X0, _Y0);
		//_glVertex2i(_X1, _Y1);
	_glEnd();
	_glDisable(GL_LINE_SMOOTH);
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::DrawRect(int _X0, int _Y0, int _X1, int _Y1, color32 _Color00, color32 _Color10, color32 _Color01, color32 _Color11)
{
	assert(m_Drawing==true);

	/*
	// border adjustment
	if(_X0<_X1)
		++_X1;
	else if(_X0>_X1)
		++_X0;
	if(_Y0<_Y1)
		++_Y1;
	else if(_Y0>_Y1)
		++_Y0;
	*/
	// border adjustment
	if(_X0<_X1)
		++_X1;
	else if(_X0>_X1)
		++_X0;
	if(_Y0<_Y1)
		--_Y0;
	else if(_Y0>_Y1)
		--_Y1;
	const GLfloat dx = +0.0f;
	const GLfloat dy = +0.0f;

	_glDisable(GL_TEXTURE_2D);
	_glMatrixMode(GL_MODELVIEW);
	_glLoadIdentity();
	//GLubyte r = GLubyte(_Color>>16);
	//GLubyte g = GLubyte(_Color>>8);
	//GLubyte b = GLubyte(_Color);
	//GLubyte a = GLubyte(_Color>>24);
	//_glColor4ub(GLubyte(_Color>>16), GLubyte(_Color>>8), GLubyte(_Color), GLubyte(_Color>>24));
	//_glColor4ub(r, g, b, a);
	_glBegin(GL_QUADS);
		_glColor4ub(GLubyte(_Color00>>16), GLubyte(_Color00>>8), GLubyte(_Color00), GLubyte(_Color00>>24));
		_glVertex2f((GLfloat)_X0+dx, (GLfloat)_Y0+dy);
		_glColor4ub(GLubyte(_Color10>>16), GLubyte(_Color10>>8), GLubyte(_Color10), GLubyte(_Color10>>24));
		_glVertex2f((GLfloat)_X1+dx, (GLfloat)_Y0+dy);
		_glColor4ub(GLubyte(_Color11>>16), GLubyte(_Color11>>8), GLubyte(_Color11), GLubyte(_Color11>>24));
		_glVertex2f((GLfloat)_X1+dx, (GLfloat)_Y1+dy);
		_glColor4ub(GLubyte(_Color01>>16), GLubyte(_Color01>>8), GLubyte(_Color01), GLubyte(_Color01>>24));
		_glVertex2f((GLfloat)_X0+dx, (GLfloat)_Y1+dy);
	_glEnd();
}

//	---------------------------------------------------------------------------

void *CTwGraphOpenGL::NewTextObj()
{
	return new CTextObj;
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::DeleteTextObj(void *_TextObj)
{
	assert(_TextObj!=NULL);
	delete static_cast<CTextObj *>(_TextObj);
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::BuildText(void *_TextObj, const std::string *_TextLines, color32 *_LineColors, color32 *_LineBgColors, int _NbLines, const CTexFont *_Font, int _Sep, int _BgWidth)
{
	assert(m_Drawing==true);
	assert(_TextObj!=NULL);
	assert(_Font!=NULL);

	if( _Font != m_FontTex )
	{
		UnbindFont(m_FontTexID);
		m_FontTexID = BindFont(_Font);
		m_FontTex = _Font;
	}
	CTextObj *TextObj = static_cast<CTextObj *>(_TextObj);
	TextObj->m_TextVerts.resize(0);
	TextObj->m_TextUVs.resize(0);
	TextObj->m_BgVerts.resize(0);
	TextObj->m_Colors.resize(0);
	TextObj->m_BgColors.resize(0);

	int x, x1, y, y1, i, Len;
	unsigned char ch;
	const unsigned char *Text;
	color32 LineColor = COLOR32_RED;
	for( int Line=0; Line<_NbLines; ++Line )
	{
		x = 0;
		y = Line * (_Font->m_CharHeight+_Sep);
		y1 = y+_Font->m_CharHeight;
		Len = (int)_TextLines[Line].length();
		Text = (const unsigned char *)(_TextLines[Line].c_str());
		if( _LineColors!=NULL )
			LineColor = (_LineColors[Line]&0xff00ff00) | GLubyte(_LineColors[Line]>>16) | (GLubyte(_LineColors[Line])<<16);

		for( i=0; i<Len; ++i )
		{
			ch = Text[i];
			x1 = x + _Font->m_CharWidth[ch];

			TextObj->m_TextVerts.push_back(Vec2(x , y ));
			TextObj->m_TextVerts.push_back(Vec2(x1, y ));
			TextObj->m_TextVerts.push_back(Vec2(x , y1));
			TextObj->m_TextVerts.push_back(Vec2(x1, y ));
			TextObj->m_TextVerts.push_back(Vec2(x1, y1));
			TextObj->m_TextVerts.push_back(Vec2(x , y1));

			TextObj->m_TextUVs.push_back(Vec2(_Font->m_CharU0[ch], _Font->m_CharV0[ch]));
			TextObj->m_TextUVs.push_back(Vec2(_Font->m_CharU1[ch], _Font->m_CharV0[ch]));
			TextObj->m_TextUVs.push_back(Vec2(_Font->m_CharU0[ch], _Font->m_CharV1[ch]));
			TextObj->m_TextUVs.push_back(Vec2(_Font->m_CharU1[ch], _Font->m_CharV0[ch]));
			TextObj->m_TextUVs.push_back(Vec2(_Font->m_CharU1[ch], _Font->m_CharV1[ch]));
			TextObj->m_TextUVs.push_back(Vec2(_Font->m_CharU0[ch], _Font->m_CharV1[ch]));

			if( _LineColors!=NULL )
			{
				TextObj->m_Colors.push_back(LineColor);
				TextObj->m_Colors.push_back(LineColor);
				TextObj->m_Colors.push_back(LineColor);
				TextObj->m_Colors.push_back(LineColor);
				TextObj->m_Colors.push_back(LineColor);
				TextObj->m_Colors.push_back(LineColor);
			}

			x = x1;
		}
		if( _BgWidth>0 )
		{
			TextObj->m_BgVerts.push_back(Vec2(-1		, y ));
			TextObj->m_BgVerts.push_back(Vec2(_BgWidth+1, y ));
			TextObj->m_BgVerts.push_back(Vec2(-1		, y1));
			TextObj->m_BgVerts.push_back(Vec2(_BgWidth+1, y ));
			TextObj->m_BgVerts.push_back(Vec2(_BgWidth+1, y1));
			TextObj->m_BgVerts.push_back(Vec2(-1		, y1));

			if( _LineBgColors!=NULL )
			{
				color32 LineBgColor = (_LineBgColors[Line]&0xff00ff00) | GLubyte(_LineBgColors[Line]>>16) | (GLubyte(_LineBgColors[Line])<<16);
				TextObj->m_BgColors.push_back(LineBgColor);
				TextObj->m_BgColors.push_back(LineBgColor);
				TextObj->m_BgColors.push_back(LineBgColor);
				TextObj->m_BgColors.push_back(LineBgColor);
				TextObj->m_BgColors.push_back(LineBgColor);
				TextObj->m_BgColors.push_back(LineBgColor);
			}
		}
	}
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::DrawText(void *_TextObj, int _X, int _Y, color32 _Color, color32 _BgColor)
{
	assert(m_Drawing==true);
	assert(_TextObj!=NULL);
	CTextObj *TextObj = static_cast<CTextObj *>(_TextObj);

	if( TextObj->m_TextVerts.size()<4 && TextObj->m_BgVerts.size()<4 )
		return; // nothing to draw

	_glMatrixMode(GL_MODELVIEW);
	_glLoadIdentity();
	_glTranslatef((GLfloat)_X, (GLfloat)_Y, 0);
	_glEnableClientState(GL_VERTEX_ARRAY);
	if( (_BgColor!=0 || TextObj->m_BgColors.size()==TextObj->m_BgVerts.size()) && TextObj->m_BgVerts.size()>=4 )
	{
		_glDisable(GL_TEXTURE_2D);
		_glVertexPointer(2, GL_FLOAT, 0, &(TextObj->m_BgVerts[0]));
		if( TextObj->m_BgColors.size()==TextObj->m_BgVerts.size() && _BgColor==0 )
		{
			_glEnableClientState(GL_COLOR_ARRAY);
			_glColorPointer(4, GL_UNSIGNED_BYTE, 0, &(TextObj->m_BgColors[0]));
		}
		else
		{
			_glDisableClientState(GL_COLOR_ARRAY);
			_glColor4ub(GLubyte(_BgColor>>16), GLubyte(_BgColor>>8), GLubyte(_BgColor), GLubyte(_BgColor>>24));
		}
		_glDrawArrays(GL_TRIANGLES, 0, (int)TextObj->m_BgVerts.size());
	}
	_glEnable(GL_TEXTURE_2D);
	_glBindTexture(GL_TEXTURE_2D, m_FontTexID);
	_glEnableClientState(GL_TEXTURE_COORD_ARRAY);
	if( TextObj->m_TextVerts.size()>=4 )
	{
		_glVertexPointer(2, GL_FLOAT, 0, &(TextObj->m_TextVerts[0]));
		_glTexCoordPointer(2, GL_FLOAT, 0, &(TextObj->m_TextUVs[0]));
		if( TextObj->m_Colors.size()==TextObj->m_TextVerts.size() && _Color==0 )
		{
			_glEnableClientState(GL_COLOR_ARRAY);
			_glColorPointer(4, GL_UNSIGNED_BYTE, 0, &(TextObj->m_Colors[0]));
		}
		else
		{
			_glDisableClientState(GL_COLOR_ARRAY);
			_glColor4ub(GLubyte(_Color>>16), GLubyte(_Color>>8), GLubyte(_Color), GLubyte(_Color>>24));
		}

		_glDrawArrays(GL_TRIANGLES, 0, (int)TextObj->m_TextVerts.size());
	}

	_glDisableClientState(GL_VERTEX_ARRAY);
	_glDisableClientState(GL_TEXTURE_COORD_ARRAY);
	_glDisableClientState(GL_COLOR_ARRAY);
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::ChangeViewport(int _X0, int _Y0, int _Width, int _Height, int _OffsetX, int _OffsetY)
{
	if( _Width>0 && _Height>0 )
	{
		GLint vp[4];
		vp[0] = _X0;
		vp[1] = _Y0;
		vp[2] = _Width-1;
		vp[3] = _Height-1;
		_glViewport(vp[0], m_WndHeight-vp[1]-vp[3], vp[2], vp[3]);

		GLint matrixMode = 0;
		_glGetIntegerv(GL_MATRIX_MODE, &matrixMode);
		_glMatrixMode(GL_PROJECTION);
		_glLoadIdentity();
		_glOrtho(_OffsetX, _OffsetX+vp[2], vp[3]-_OffsetY, -_OffsetY, -1, 1);
		_glMatrixMode(matrixMode);
	}
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::RestoreViewport()
{
	_glViewport(m_ViewportInit[0], m_ViewportInit[1], m_ViewportInit[2], m_ViewportInit[3]);

	GLint matrixMode = 0;
	_glGetIntegerv(GL_MATRIX_MODE, &matrixMode);
	_glMatrixMode(GL_PROJECTION);
	_glLoadMatrixf(m_ProjMatrixInit);
	_glMatrixMode(matrixMode);
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::SetScissor(int _X0, int _Y0, int _Width, int _Height)
{
	if( _Width>0 && _Height>0 )
	{
		_glScissor(_X0-1, m_WndHeight-_Y0-_Height, _Width-1, _Height);
		_glEnable(GL_SCISSOR_TEST);
	}
	else
		_glDisable(GL_SCISSOR_TEST);
}

//	---------------------------------------------------------------------------

void CTwGraphOpenGL::DrawTriangles(int _NumTriangles, int *_Vertices, color32 *_Colors, Cull _CullMode)
{
	assert(m_Drawing==true);

	const GLfloat dx = +0.0f;
	const GLfloat dy = +0.0f;

	GLint prevCullFaceMode, prevFrontFace;
	_glGetIntegerv(GL_CULL_FACE_MODE, &prevCullFaceMode);
	_glGetIntegerv(GL_FRONT_FACE, &prevFrontFace);
	GLboolean prevCullEnable = _glIsEnabled(GL_CULL_FACE);
	_glCullFace(GL_BACK);
	_glEnable(GL_CULL_FACE);
	if( _CullMode==CULL_CW )
		_glFrontFace(GL_CCW);
	else if( _CullMode==CULL_CCW )
		_glFrontFace(GL_CW);
	else
		_glDisable(GL_CULL_FACE);

	_glDisable(GL_TEXTURE_2D);
	_glMatrixMode(GL_MODELVIEW);
	_glLoadIdentity();
	_glBegin(GL_TRIANGLES);
	for(int i=0; i<3*_NumTriangles; ++i)
	{
		color32 col = _Colors[i];
		_glColor4ub(GLubyte(col>>16), GLubyte(col>>8), GLubyte(col), GLubyte(col>>24));
		_glVertex2f((GLfloat)_Vertices[2*i+0]+dx, (GLfloat)_Vertices[2*i+1]+dy);
	}
	_glEnd();

	_glCullFace(prevCullFaceMode);
	_glFrontFace(prevFrontFace);
	if( prevCullEnable )
		_glEnable(GL_CULL_FACE);
	else
		_glDisable(GL_CULL_FACE);
}

//	---------------------------------------------------------------------------
}
#endif // ANT_TW_NO_LEGACY_GL
